Plant regeneration from callus culture of Cymbidium ensifolium var. misericors

Totipotent calli of Cymbidium ensifolium var. misericors, a locally grown orchid of high commercial value, were induced from sections of pseudobulbs, rhizomes and roots of seed-derived plantlets on 1/2-strength Murashige and Skoog medium plus 10 mg/l 2,4-dichlorophenoxyacetic acid and 0.1 mg/l thiadiazuron. The calli could be maintained by subculturing in the same medium. The calli could be induced to develop further along one of three distinct morphogeneic routes: (1) production of rhizomes, (2) production of shoot buds, or (3) development of granular embryoids. Efficient mass propagation was possible via rhizome proliferation and embryoid formation. Received: 28 May 1997 / Revision received: 19 August 1997 / Acceptance: 2 September 1997     

Fungal elicitor preparations and methyl jasmonate enhance rosmarinic acid accumulation in suspension cultures of Coleus blumei

bstract Suspension cultures of Coleus blumei (Lamiaceae) treated with either an elicitor preparation from the culture medium of the phytopathogenic oomycete Pythium aphanidermatum or with methyl jasmonate enhanced accumulation of rosmarinic acid approximately threefold. The specific activities of phenylalanine ammonia lyase and rosmarinic acid synthase were also enhanced after addition of the fungal elicitor. The addition of methyl jasmonate transiently increased activities of phenylalanine ammonia lyase and hydroxyphenylpyruvate reductase, whereas the activity of rosmarinic acid synthase was not stimulated and the activity of tyrosine aminotransferase was slightly and constantly enhanced. Methyl jasmonate stimulated rosmarinic acid accumulation not only when added directly to the culture medium, but also when it could reach the cells only via the gas phase. Received: 2 April 1997 / Revision received:16 June 1997 / Accepted: 15 September 1997     

Embryogenesis and plant regeneration from callus cultures derived from unpollinated ovaries of Hyoscyamus muticus L.

Unpollinated ovaries of Hyoscyamus muticus L. (commonly known as Egyptian henbane) were cultured on Murashige and Skoog and Bourgin and Nitsch media supplemented with various growth hormones to study the organogenesis, embryogenesis and regeneration of plantlets. Embryogenesis was reported for callus grown on both media containing 0.05 mg/l α-naphthaleneacetic acid and 0.5 mg/l 6-benzylaminopurine. Differentiation of roots and shoots from the calli also occurred in these media. Albinism or chlorophyll deficiency and variation in ploidy level were observed among the ovary-derived plantlets. Received: 7 April 1997 / Revised received: 2 August 1997 / Accepted: 2 September 1997     

Potential for biodegradation of hydrocarbons in soil from the Ross Dependency, Antarctica

Oil spills occur in the Antarctic when fuel oils such as JP8 jet fuel are moved or stored. Hydrocarbons, both n-alkanes and aromatic compounds, have been detected in oil-contaminated soils of the Ross Dependency. In such areas hydrocarbon-degrading microbes, if naturally occurring, could be used for clean-up. Soil samples from oil-impacted and control sites were analysed for hydrocarbon-degrading microbes and for a range of parameters known to limit biodegradative activity. Soils were analysed for water content, pH, concentrations of nutrients (N and P) and electrical conductivity. Numbers of culturable heterotrophic bacteria and hydrocarbon degraders were greater in some of the oil-contaminated samples. Mineralisation studies with ¹⁴C-radiolabelled hexadecane and naphthalene demonstrated that nitrogen amendments significantly enhanced hydrocarbon mineralisation rates in an oil-impacted soil. Received: 30 June 1997 / Received revision: 15 September 1997 / Accepted: 19 September 1997     

Biotechnological production of flavours and fragrances

The biotechnological generation of natural aroma compounds is rapidly expanding. Aroma chemicals, such as vanillin, benzaldehyde (bitter almond, cherry) and 4-(R)-decanolide (fruity–fatty) are marketed on a scale of several thousand tons per year. Their possible production by single-step biotransformations, bioconversions and de novo synthesis using microorganisms, plant cells or isolated enzymes is shown. The perspectives of bioprocesses for the oxifunctionalisation of lower terpenes by genetically modified organisms and economic aspects are discussed. Received: 27 May 1997 / Received revision: 25 September 1997 / Accepted: 28 September 1997     

Mercury, cadmium and lead accumulation in Antarctic mosses growing along nutrient and moisture gradients

Accumulation of Hg, Cd and Pb by moss was studied in a coastal ice-free area (Edmonson Point, northern Victoria Land) in relation to the water and nutrient availability and substratum characteristics. Although metal concentrations in surface soils were among the lowest ever reported from remote areas, those of Hg and Cd in mosses were higher, being in the same range as those usually reported in regional surveys in the northern hemisphere. By contrast, Antarctic mosses showed very low Pb concentrations, and no impact from local human activities was detected. Marine aerosols, seabird guano and volcanic emissions appeared to be the more probable sources of Cd and Hg. Besides atmospheric deposition, the main pathway of metals to mosses was probably through evapo-transpiration at their surface which determines an upward migration of ions and their bioaccumulation. Received: 8 September 1997 / Accepted: 4 January 1998     

Estimation of the Transition/Transversion Ratio

A simple method for estimating the transition/transversion ratio was developed. This method can be applied to not only two sequences but also more than two sequences. The statistical properties of the method and some other methods were examined by numerical computation and computer simulation. The results obtained showed that, in terms of bias and variance, the new method gives a better estimate of the transition/transversion ratio than do the other examined methods. The new method was applied to human and chimpanzee mitochondrial control region sequences. Received: 22 September 1997 / Accepted: 1 November 1997     

Cell-Surface Lectins of Azospirillum spp.

Cell-surface lectins were screened in seven strains of Azospirillum brasilense and A. lipoferum. The presence of lectins was determined by particle agglutination assays employing latex beads coated with neoglycoproteins and by Western blot with neoglycoproteins labeled with horseradish peroxidase as a probe. Seven strains were agglutinated with the assayed sugar residues. The highest agglutination was with fucose and glucose and to a lesser extent with mannose residues. Cell-wall proteins extracted from two Azospirillum spp. strains exhibit lectin-like activities. We believe that lectins are present in the cell-wall of Azospirillum spp. Received: 23 June 1997 / Accepted: 23 September 1997     

The mutational-response index and codon bias in genes from a Frankia nif operon

 The mutational response index (MRI) and measurements of codon bias were determined in three characterised genes, and two open reading frames of unknown function, from the Frankia nif operon, which encodes genes for nitrogen fixation. The merits of the different systems of measuring codon usage are discussed in the light of the results, as are the applicability of these techniques to the assessment of the translational function of putative open reading frames. Received: 8 August 1997 / Accepted: 19 September 1997     

Genetic mapping of the mouse ferritin light chain gene and 11 pseudogenes on 11 mouse chromosomes

We typed the progeny of two sets of genetic crosses to determine the map locations for loci containing sequences related to the ferritin light chain (Ft11) gene. Twelve loci were positioned on 11 different chromosomes. One of these genes mapped to a position on Chr 7 predicted to contain the expressed gene on the basis of the previously determined position of the human homolog on 19q13.3-q13.4. Received: 23 July 1997 / Accepted: 20 September 1997     

Anaerobic leaching of covellite by Thiobacillus ferrooxidans

Thiobacillus ferrooxidans was able to grow under anaerobic conditions on copper sulphide with ferric ion as the electron acceptor. The dissolution of covellite under these conditions (68% after 35 days) was higher than values observed aerobically in cultures with similar media composition and almost as high as under aerobic conditions without iron. From these results we propose a mechanism for anaerobic bioleaching of covellite in the presence of ferric iron and speculate that it may occur in leach dumps where the oxygen concentration is, as reported elsewhere, very low. Received: 3 September 1996 / Received revision: 13 January 1997 / Accepted: 24 January 1997     

Spontaneous mutation in a thermoacidophilic archaeon: evaluation of genetic and physiological factors

We used direct selection of pyrE and pyrF mutants to estimate the rates of spontaneous mutation in Sulfolobus acidocaldarius as a function of genetic background and culture conditions. Fluctuation tests were applied to several genetically marked strains, including one isolated as a putative mutator strain, and to cultures grown over a wide range of temperature and other physiological conditions. The results suggested some impact of auxotrophic markers on the apparent rate of mutation, but no obvious pattern of effect of growth conditions, including those that gave evidence of being physiologically stressful. Received: 27 May 1997 / Accepted: 2 September 1997     

Relationship Between Serotype A Encapsulation and a 40-kDa Lipoprotein in Pasteurella multocida

Eleven serotype A encapsulated and nonencapsulated strains of Pasteurella multocida were examined with regard to lipoprotein content. Relative amounts of an approximately 40-kDa lipoprotein (Plp-40) were found to correlate directly with the degree of encapsulation in that heavily encapsulated strains exhibited the greatest amounts, while nonencapsulated strains possessed little or no Plp-40. Received: 29 September 1997 / Accepted: 31 October 1997     

Low-molecular-weight precursors for defense-related cell wall hydroxycinnamoyl esters in elicited parsley suspension cultures

Cell walls from suspension cultures of parsley (Petroselinum crispum L.) induced with a fungal elicitor contained hydroxycinnamoyl ester groups presumably not bound to pectic polysaccharides. Extracts from these cells were separated into a range of low-molecular-weight compounds containing esterified ferulic and p-coumaric acid as well as glucose and some arabinose. Similar compounds also accumulated extracellularly in elicited cultures but only in the presence of the peroxidase inhibitor ascorbate, suggesting that they may represent the exported precursors for cell wall hydroxycinnamic acids. From cultures elicited in the presence of ascorbate, alkali released from the cell walls more ferulic, p-coumaric and p-hydroxybenzoic acid, as well as p-hydroxybenzaldehyde and vanillin, indicating that the corresponding wall phenolics can all become further cross-linked. Received: 6 September 1996 / Revision received: 10 March 1997 / Accepted: 10 April 1997     

Activity of the CaMV 35S promoter in various parts of transgenic early flowering birch clones

Early flowering together with small size would be useful for various biotechnical or genetic studies on trees. We report here the selection and micropropagation of early flowering birch (Betula pendula) clones (BPM1–12) obtained from seeds of birches bred elsewhere for early flowering. Under conditions that accelerate flowering (a high CO₂ level, strong and continuous illumination), the first male inflorescences emerged in 3–5 months, the trees then being 20–80 cm high. Transgenic lines (CaMV 35S-GUS INT) were produced through Agrobacterium-mediated gene transfer from BPM2, BPM5 and JR1/4 (a normally flowering birch). β-Glucuronidase (GUS) activities in the different lines, assayed 1–1.5 years after transformation, varied greatly. During further in vitro culture for 10 months, the activities decreased to 0.3–7% of the original values. GUS activities were detected in all organs studied, including the developing male inflorescences; the highest activity was in the roots. Received: 28 April 1997 / Revision received: 5 September 1997 / Accepted: 30 November 1997     

Biohydrometallurgical processing of solids: a patent review

Autotrophic as well as heterotrophic bacteria and fungi play an important role for the industrial recovery of metals from low-grade ore or, in general, from low-grade mineral resources. The same inorganic bacterial pathways that are responsible for huge and expensive corrosion problems can be used for economical biohydrometallurgical applications. Metals and metalloids can be microbially transformed by oxidation, reduction, alkylation, dealkylation, solubilization, and␣precipitation mechanisms. Biohydrometallurgy, a branch of classical metallurgy, is not as widely publicized as other areas of metallurgy, e.g. pyrometallurgical or hydrometallurgical processes. Since 1990, approximately 15 international patent applications concerning biohydrometallurgical techniques have been claimed under the Patent Cooperation Treaty in contrast to a large number of patents concerning pyro- and hydrometallurgical techniques. Nevertheless, it is a very important field of investigation, especially for the future when aspects of a sustainable development have to be considered. New processes to support this development are applicable, at least on a laboratory scale. Bacterial leaching processes for the recovery of metals from solid residues are applied for low-grade ore, and, more recently, for fly ash, galvanic sludges, or, in general, for industrial wastes. It is possible to recover leached metals and to recycle them in metal-manufacturing industries. In addition, by removing the metals from residues, the environmental quality is improved, and the material can be re-used for construction purposes. Received: 21 April 1997 / Received revision: 14 July 1997 / Accepted: 27 July 1997     

Discrete chiasma formation models and their associated high order interference

. We introduce some special chiasma formation processes. First a family of discrete chiasma formation processes is introduced and we determine the nature of higher order interference associated with those processes. Secondly we consider a two-stage chiasma formation process, where the associated recombination frequency between two markers depends not only on their map distance but also on their location along the chromosomes. We characterise under this process, in some cases, the nature of interference between two segments. Received: 22 January 1996 / Revised version: 17 September 1997     

Construction of a low-serine-type-carboxypeptidase-producing mutant of Aspergillus oryzae by the expression of antisense RNA and its use as a host for heterologous protein secretion

Using an antisense control strategy, we isolated an Aspergillus oryzae mutant that produced low levels of carboxypeptidases (CPases). The mutant TF_C-1 expressed the antisense RNA of the structural gene of CPase O and showed about 30% of the CPase activity in the parent strain. Gel filtration analysis indicated that this mutant decreased the CPase activities not only of CPase O but also of CPase O-1 and O-2. This result indicated that the antisense RNA was able to control the expression of the CPase genes as a group. Using the mutant as a heterologous protein expression host that produced the low levels of CPases, a stable and higher level of lysozyme expression could be obtained compared with the wild-type. In vitro proteolytic degradation assay also demonstrated that human lysozyme was degraded by purified CPase O. Received: 16 June 1997 / Received last revision: 29 August 1997 / Accepted: 15 September 1997     

On the occurrence of males and production of ephippial eggs in populations of Daphniopsis studeri (Cladocera) in lakes of the Vestfold and Larsemann Hills, East Antarctica

Populations of the cladoceran Daphniopsis studeri Rühe in freshwater and brackish lakes of eastern Antarctica have been thought to consist solely of females that reproduce parthenogenetically by the production of ameiotic subitaneous eggs. This note reports the presence of male D. studeri and the production of ephippial (sexual) eggs in a number of lakes of the Vestfold and Larsemann Hills, which indicate the possibility of sexual reproduction within these populations. Received: 12 May 1997 / Accepted: 8 September 1997     

Production of indole-3-acetic acid by mutant strains of Ustilago maydis (maize smut / huitlacoche)

Production of indole-3-acetic acid (IAA) by four strains of the maize pathogen Ustilago maydis was analyzed. The fungus induces gall formation on its host plant and IAA production by  U. maydis may be required as a pathogenicity or virulence factor. The study included the FB2 wild-type strain and the 103, 130FZ and 130FT mutants. Results show that treatment with clofibric acid, alone or in combination with UV light, can be used to obtain  U. maydis strains with defective IAA production in vitro, as quantified with the Salkowski reagent and by HPLC. The strain with the lowest production was 130FT, and its peak IAA level represented only 16% of the highest value obtained for the FB2 wild-type strain (124 μg/ml). Received: 11 April 1996 / Received last revision: 5 September 1997 / Accepted: 11 September 1997